Suction sweeper



Dec. 27, 1927. 1,654,185

M. E. NULSEN SUCTION SWEEPER Filed June 6, 1921 2 Sheets-Sheet l I i I M" .mmnnmmmr l i I I is I on Cpeninq J lnven-l'or Marvin E. Nulsen Afiorney Dec. 27, 1927. 1,654,186

"M. E. NULSEN SUCTION SWEEPER Filed June 6, 1921 2 Sheets-Sheat 2 lnvenror" Marvin E. Nulsen y A'Horney.

the longitudinal curvature of the front and rear lips 20 and 21 respectively, and in a similar manner, the surfaces of the front and rear lips are curvedtransversely to form a continuation of the curvature of the end lips. This transverse curvature of the lips prevents the edges from digging down into the pile of the carpet which would tend-tocut off the transverse flow of air through and around the pile threads as well as have a destructive effect on the same. The curvature of the suction lips described in the foregoing is comparatively small, and, therefore, the force required to bend the'carpet into'the curve is quite small compared to the tension inthe carpet. The direction and relative magnitudes of the forces acting on the carpet are indicated in the diagram designated as Figmfi of the drawings, in which ,ector A'B=weight of a unit area of carpet.

Vector A C=unbalanced air pressure (suction) acting on a unit area of carpet.

Vector C D=Vector A B.

Vector A D=resultant of suction and weight per unit area.

Then for zero contact pressure between lip and carpet pile, the shaded area, of which A D is. an element, represents the force which is balanced by the tension T in the carpet, and for a positive contact pressure between lip and carpet pile, vectors A D and the height of the shaded area will be shortened, and h, Z, (,Z, 9, and T will be lessened. But the shortened (in height) shaded area will still represent the force which is balanced by the decreased T, and the decrease in shaded area will represent the contact pressure between lip and carpet. It is thus seen that the carpet curve is in effect practically that of a suspended cable of uniform Weight; the decreased (in height) shaded area represents the uniform cable weight, and the decreased T represents the cable tension. The curve taken by a suspended cable is the catenary, and for the flat arcs under discussion, the catenary closely resembles the parabola.

'A simple way. to determine the equation of this curve is to measure experimentally the angle 6 which is the angle made with the horizontal by the tangent atthe point of contact with the lip. Then, taking the equation of the parabola when the origin is at the Vertex, we have-- 1 2m 3/ J2me The slope at any point The slope at point P, where a la, is

. 1 tan =COl3 9 solving for 2a.

lh=S tan 9 (3) Substitute in (2) the value of 1-h (3) 2a=S tan 6 cot G=S cot 6 (4) Substituting in (1) the value of 200 (at) 3 (S cot 6) a or Y tan 9 w:q s cot9 s (5) The measured value of 6 and S for the particular suction opening in question, should be inserted in equation (5). Then the exact contour of the suction opening can easily be laid ofi. with the aid of the resulting equation.

Under a suction nozzle of this construction a wave in the carpet is formed having a crest with its greatest height situated in the diametrical center of the nozzle. In order to properly beat and sweep a carpet under a nozzle of this sort, i. 0., one having all four lips of the nozzle curved, it is desirable that the brush or beating device used have a conformation following that of the longitudinal curvature of the front and rear lips of the nozzle. Such a brush is illustrated in Figure 2.

In another embodiment of my invention, as illustrated by Figures (3, 7, and 8 of the drawings, I have shown a suction nozzle with the front and rear lips 22 and 2;; respectively formed substantially straight and in which the end lips 19 are curved to conform to the wave formed in the carpet by the suction. In this modification, the front and rear lips would be curved transversely as shown in Fig. 8 .with the same curvature as the end lips and no longitudinal curvature would be given to the front and rear lips. Under a suction nozzle of this construction a wave in the carpet is formed having a crest of substantially uniform height along its length within the confines of the nozzle. To co-operate with such a nozzle I,

' therefore, prefer a beating and sweeping ill is provided with a series of indentations 27 cut in the suriace thereof and substantially equally spaced from each other. By providing the nozzle lips with an interrupted sur lace of this sort in lieu of the uninterrupted surfaces as shown in the other figures, the majority of the pile on the carpet is not crushed down as the lips pass orer the same. Furthermore, this construction provides a passageway il'or the blast oi air created by the suction device which is transverse to the; pile threads,

a condition conducive to ethcient cleaning.

l claim:

l, in suction-cleaner, a suction-nozzle having the lips thereof curred arcuately in relation to a horizontal plane, and a rug contacting cleaning element operable within said nozzle and having a longitudinal peripheral curvature substantially correspondtill 7 hrushrjournaled .within said nozzleand hav ing with that of said lips.

2 13 a suction-cleaner, a suction-nozzle having the lips thereofcurved arcuately in relation to a'horizontal plane, and a rotarying a longitudinal peripheral curvature substantially corresponding with that hi said lips.

. 33in a suction-oleanenia suction-nozzle having arcuately-curved' lips, and a rotary cleaning elementlocated within said nozzle and having a longitudinal peripheral curvature-approximating that'of said lips.

4. In a suotion cleaner asuction-nozzle having the. lips thereof iormed with their opppsite' end port ons upwardly and inwardlyinclined to form a seal with the suction elevated portion or bulge of an underlying floor-covering, and a sweeping element oper able within said nozzle and shaped to con form throughout to the nozzle-sealing por tion oi the bulge of said floor-covering.

5. In a suction sweeper having a suction producing means and a downwardly opening inlet nozzle, side and end walls having lips defining the nozzle opening, means sus taining the nozzle opening in spaced relation to a material to be cleaned, the sustain-- ing means positioned to allow the material to be ireelyraised to the nozzle opening, the end nozzle defining lips heing upwardly curved from their ends toward their centers.

7 6.. in a suction sweeper having suction H producing means and a downwardly open front and back nozzle defining lips being upwardly curved from. their ends toward their centers. i y

7. A suction sweeperhaving suction producing means and a downwardly opening inlet nozzle, side and end walls having lips defining the nozzle opening, means sustain ing the nozzle opening in spaced relation to the material to be cleaned, the sustaining means positioned to allow"v the material to be freely raiwcl to thenozzle opening, each of Evil the nozzle defining lips being upwardly curved from its ends toward its center.

@Signed at North Canton, in the county of: Stark and State of- Ohio, this 27th day of May, A. D. 1921.

MARVIN a. "mean. 

